Nowadays, network communication is necessary for modern people. Hundreds and thousands of people are involved in the various services provided by the network. However, because the bandwidth of the network has a limitation, monitoring network traffic volume of each kind of the service is required for distributing the traffic to each kind of the service in the limited bandwidth situation. Furthermore, in some situations, the traffic volume of an individual user needs to be limited so the network traffic volume of each user also may need to be monitored.